Is this pipework ok?

[pejoli]

Any opinions on this - the pipework is proud of the plywood, and will still be sticking out after the backing board is on - only the tile adhesive will give enough clearance for the tile to go over it.

Are there any issues with this, other than not looking the most beautiful setup in the world? Will it cause any problems down the line?

Thanks.

P.S. I added some pictures to an album - not sure how to make them show up

added by Mod10:

Untitled

• pejoli
• 16 Jun 2010
• 1

Untitled

• pejoli
• 16 Jun 2010
• 1

 

[Richard C]

I would not have used ply as a base for start, it’s not dimensionally stable when exposed to moisture & why on earth have you used those crappy plastic plumbing fittings ; copper would probably given you enough clearance. The problem with having the pipe work not fully covered & exposed to the adhesive is thermal expansion/contraction of the pipe/fitting will almost certainly crack the adhesive/grout, water gets in & there go your tiles. What backer boards are you using? What size/weight tiles are you using?

 

[pejoli]

It's not me doing it, it's my builder ....

The backing board will be plasterboard, which will be plastered, and then tiled.

Having spoken to him this morning, he says that they'll put a scrim over the hole and plaster over that - so there won't be a void behind the tile itself. He seems to think they'll be enough clearance, but it looks tight to me. How much clearance should there typically be between that pipe and any other surface to avoid expansion issues?

The reason for piping is to carry the flow from the top of the valve (it's a grohe 2000 3/4") behind the board it's mounted on and back up at the bottom to go into an elbow for the shower flex.

He's also chosen to reduce down from 22mm to 15 on that last stretch - otherwise the last elbow would have been smaller.

How do I tell if he's got it right (he insists it will be fine) ? And how as a client do I tell him I want it done differently without him charging me for all the rework, if he doesn't agree with my opinion? Or do I just trust him as he is the professional?

 

[Richard C]

My word he’s doing some really old fashioned stuff there, presumably he's responsible for the plastic fittings as well; personally, I would never use plastic even though some say that is old fashioned. Ply in a wet area is really not a good idea unless tanked & even then the back is still vulnerable to water problems if the valve leaks & no amount of tanking on the front will help with that. You should not use PB in wet areas unless it’s tanked & then only Moisture Resistant PB; water proof backer boards are much better & is what I always use. Plastering PB is completely unnecessary & a waste of time/money if your tiling over it, the size/weight of tiles you can hang on it will also be seriously reduced; just tank it & tile away. What size/weight tiles are you hanging?

The pipe work should be 22mm all the way up to the valve, only reduce to 15mm after to the head. The pipe work must be allowed to expand/contract behind the tile base & not be directly under or in contact with the tiles or the adhesive. I think it will almost certainly lead to cracking & tile failure. Looking at your pics. I’m not even sure the valve has been set back far enough which may affect the tile plate fitting.

I’m not overjoyed by what you’ve said & I would never do some of the things he’s doing. It would have been better to have done a little research before hand so you can tell if the guy is any good before you employ him. A read through the tiling forum archive will give you a good grounding both from myself & several other pro tillers/bathroom fitters/renovators. I don’t really know how best to advise you but it’s not looking like it’ll be the best of jobs to me & I would be very unhappy with it.

 

[pejoli]

Thanks for the quick reply - some answers:

My word he’s doing some really old fashioned stuff there, presumably he's responsible for the plastic fittings as well; personally, I would never use plastic even though some say that is old fashioned. Ply in a wet area is really not a good idea unless tanked & even then the back is still vulnerable to water problems if the valve leaks & no amount of tanking on the front will help with that.

Is this true even for WBP or exterior ply that's 'waterproof' - I thought this was the recommended materail for floors? What is your usual preference?

You should not use PB in wet areas unless it’s tanked & then only Moisture Resistant PB; water proof backer boards are much better & is what I always use. Plastering PB is completely unnecessary & a waste of time/money if your tiling over it, the size/weight of tiles you can hang on it will also be seriously reduced; just tank it & tile away. What size/weight tiles are you hanging?

tiles are 25x40 'wavy' white tiles (don't know the weight - nothing special), with a decorative stripe of 31x50 tiles.

The pipe work should be 22mm all the way up to the valve, only reduce to 15mm after to the head.

yep - it's 22mm after the valve, and only reduces to 15 on that last plastic connection before the elbow. My point was if he'd done that a joint or two earlier the last plastic elbow would have been smaller (but still may not have helped)

The pipe work must be allowed to expand/contract behind the tile base & not be directly under or in contact with the tiles or the adhesive. I think it will almost certainly lead to cracking & tile failure. Looking at your pics. I’m not even sure the valve has been set back far enough which may affect the tile plate fitting.

I think he measured in carefully to account for everything - they've done this lots of times (so either experienced or a repeat-offender, depending on our pov!)

I’m not overjoyed by what you’ve said & I would never do some of the things he’s doing. It would have been better to have done a little research before hand so you can tell if the guy is any good before you employ him. A read through the tiling forum archive will give you a good grounding both from myself & several other pro tillers/bathroom fitters/renovators. I don’t really know how best to advise you but it’s not looking like it’ll be the best of jobs to me & I would be very unhappy with it.

The challenge is this a complete loft build (and my first experience in have trades in). There's no way I could have known or been able to 'tech' the guy out on all the skills.

Once again, thanks for all your advice - this forum and the people on it are a great resource!

 

[Richard C]

Is this true even for WBP or exterior ply that's 'waterproof' - I thought this was the recommended materail for floors? What is your usual preference?

WBP is prefect for floors not walls & certainly not walls in a wet area as far as I’m concerned. Most bathroom floors aren’t exposed to continuous running water unless it’s a wet room & then it should be tanked but I would not use WBP in that case. It’s only the adhesive used to glue the veneers together that’s waterproof & so won’t disintegrate. WBP is still made from timber, untreated timber is not waterproof & will expand/contract/warp when it gets wet or is subject to excessive moisture. In wet areas I will always use a waterproof tile backer board by choice or if I have to use PB, only MR & then tank it.

tiles are 25x40 'wavy' white tiles (don't know the weight - nothing special), with a decorative stripe of 31x50 tiles.

With 25 x 40cm tiles you should be using a flexible cement based adhesive not tub mix. If he plasters the walls they will only take 20 kg/sqm so check the tile weight & then add on 4kg/sqm for adhesive; if your tiles weight more than 16 kg/sqm your on the limit tiling over plaster. Raw PB will take up to 32 kg/sqm, some tile backer boards can take up to 50 kg/sqm

I think he measured in carefully to account for everything - they've done this lots of times (so either experienced or a repeat-offender, depending on our pov!)

Question is how long do their jobs last; 2-4 years! A decent refurb correctly done should last 10 years but 15 -20 should be easily be possible. Check the forum archive for sob stories.

 

[Agile]

Since your hot and cold supplies are mains water derived I will have to take a differeing view on the size of pipes feeding the shower.

As it will only be taking about 10 li/min then 15 mm should be totally adequate in my opinion.

I will be interested to see how satisfied you are ( not ) with your builder's expectation that you will be able to run two showers at the same time!

Tony Glazier

 

[pejoli]

Don't worry Tony - you already 'managed my expectations' a few months back on this one when I asked a few questions about my boiler (at the start of what seems like a never ending build!)

 

[pejoli]

So the builder says it's normal plasterboard, but they plaster the whole room and then give everything two coats of unibond which will make it watertight - is that the same as 'tanking' ?

 

[powell30]

Er no. Tanking is an entirely seperate process.

That said if marine ply is used (totally waterproof and stable)you should be ok. WBP is water resistant not water proof

 

[Richard C]

Since your hot and cold supplies are mains water derived I will have to take a differeing view on the size of pipes feeding the shower.

As it will only be taking about 10 li/min then 15 mm should be totally adequate in my opinion.

I will be interested to see how satisfied you are ( not ) with your builder's expectation that you will be able to run two showers at the same time!

Tony Glazier

You obviously seem to know more about the history of certain aspects of this projects than I do.

So the builder says it's normal plasterboard,

You should only use Moisture Resistant PB in a bathroom which has to have a coat of bonding primer before skimming (not standard PVA)

but they plaster the whole room and

You can but if you’re covering it with tiles what’s the point, why bother your just wasting your money! The biggest problem is that you will reduce the weight of the tiles the PB will accept; unplastered boards will take 32 kg/sqm, plastered only 20 kg/sqm. The size of tiles your using should be fixed with a flexible powder cement based addy (not tub mix), & grout this accounts for up to 4 kg/sqm so if your builder skims the boards your tiles should not exceed around 16 kg/sqm; I advise you to check the weight of your tiles.
Don’t take my word for it, check it out on the British Gypsum website;
http://www.british-gypsum.com/pdf/SB07_Tiling_02.pdf

then give everything two coats of unibond which will make it watertight - is that the same as 'tanking' ?

Standard PVA is the last thing you should use on a tile base in wet areas & it most definitely will not make it watertight. It re-emulsifies when wet & your tiles will then fall off the wall; a few posts where this has happened in the archive. Some more reading for you;
http://www.ultimatehandyman.co.uk/forum1/pva-why-you-shouldn-t-use-it-as-a-tiling-primer-t168.html
This is what he should be using;
http://www.bal-adhesives.co.uk/products/wp1-coating
or better still, waterproof tiles backer boards

Got to say your builder doesn’t seem to have a clue what he’s talking about when it comes to forming/fitting showers, plastering or tiling; either that or he’s snowing you.

 

[mickyg]

I don't think plumbers should be worried about not getting enough work, the next 10-15 years will see us spending half our time digging out buried leaking pushfits from walls, ceilings, floors.....

 

[Richard C]

I don't think plumbers should be worried about not getting enough work, the next 10-15 years will see us spending half our time digging out buried leaking pushfits from walls, ceilings, floors.....

 

[pejoli]

then give everything two coats of unibond which will make it watertight - is that the same as 'tanking' ?

Standard PVA is the last thing you should use on a tile base in wet areas & it most definitely will not make it watertight. It re-emulsifies when wet & your tiles will then fall off the wall; a few posts where this has happened in the archive. Some more reading for you;
http://www.ultimatehandyman.co.uk/forum1/pva-why-you-shouldn-t-use-it-as-a-tiling-primer-t168.html
This is what he should be using;
http://www.bal-adhesives.co.uk/products/wp1-coating
or better still, waterproof tiles backer boards

Got to say your builder doesn’t seem to have a clue what he’s talking about when it comes to forming/fitting showers, plastering or tiling; either that or he’s snowing you.

Hmm ... well the positive note is the builder isn't doing the tiling, a tiler is subcontracted to doing it. I'll ask him all these questions. Though, ominously, when he came round to measure up and quote the other night, he thought the plaster skim would only take two-three days to be ready to tile - is this sufficient (checking the tiling forum seemed to suggest it would take much longer ...)

 

[Richard C]

He doesn’t know about tiling over new plaster skim either; 10 days (7 at least) if you tile any sooner you run the risk of trapping residual moisture under the tiles which will give poor bonding & another reason your tiles might drop off before too long especially if he uses standard PVA to prime it. A plaster base coat & skim can take up to 4 weeks to dry out but, as I said before, don’t take my word for it, do some digging on the British Gypsum website for their own technical recommendations.

You don’t seem to trust my advice I appreciate that's up to you but I only do quality refurbishment work on bath/shower rooms & am also a plasterer; I do everything that's required (except the electrics) - plastering, tiling, plumbing, fitting out. I've no idea if your builder is charging quality prices but what he's doing isn’t quality & it needn't cost much if any extra, it's usually just a question of using the correct materials & doing it properly; the tiling subby is probably your builders mate!